Patent Document 1: JP2009-22069A
Patent Document 2: JPH08-322107A
A regenerative braking technology (also referred to as a regenerative brake), which uses an electric motor-generator to generate electric power during braking and stores the electric power in a battery, is conventionally employed in a hybrid or electric vehicle described in Patent Document 1. Patent Document 1 describes a scheme for implementing a propulsion device that is used in a vehicle using a generator motor as a motive power source and is capable of preventing a battery from being overcharged, recovering energy efficiently, and reducing the wear of a mechanical brake.
As such being the case, when the vehicle is driven, the battery supplies electric power to the generator motor, which operates as a motor generator, and when the vehicle is braked, the generator motor, which operates as a generator, is used to store braking energy in the battery.
Further, a first thermoelectric conversion element connected to the generator motor uses the regenerative electric power of the generator motor to cool the generator motor. This reduces the copper loss and iron loss of the generator motor, thereby reducing electric power loss. Besides, the charging current for the battery is reduced to prevent an overcharge. Preventing the overcharge in the above manner decreases the dependence on the mechanical brake.
Furthermore, thermal energy arising from the electric power loss in the generator motor is recovered by the first thermoelectric conversion element. Moreover, thermal energy arising from battery charging/discharging can be recovered by a second thermoelectric conversion element to improve fuel efficiency. This increases the fuel efficiency and reduces the use of a friction brake.
A similar control scheme is applied to cruise control. When speed is reduced for constant-speed control, the above-mentioned regenerative braking technology is used to achieve speed reduction while recovering electric power.
However, regenerative braking cannot be applied while the battery is fully charged.
If the above situation occurs while cruise control is exercised, user-friendliness is impaired.
A heating/cooling system for optimizing the temperature of the battery already exists.
An invention disclosed in Patent Document 2 permits a vehicle to run in accordance with information supplied from a car navigation unit and prevents a battery from being over-discharged or overcharged even when the vehicle continuously runs on an uphill or a downhill. More specifically, the following configuration is employed in order to prevent the battery in a hybrid vehicle from being over-discharged or overcharged in accordance with information supplied from the car navigation unit even when the vehicle continuously runs on an uphill or a downhill.
A control section receives road information from the car navigation unit and calculates the energy required for running along a route from a current location to a destination. A generator output pattern is determined in accordance with the required running energy and with the charging capability of a generator. A target generator output is calculated in accordance with the generator output pattern and with a battery charge status. A target throttle opening and a target field current amount are calculated in such a manner that an actual generator output agrees with the target generator output. Further, a target throttle opening signal is output to a throttle actuator drive control section, and a target field current amount signal is output to a field winding current control section. In this manner, the output of the generator is controlled to maintain the battery charge status within a predetermined control range. As a result, a control schedule is organized in accordance with the road information from the car navigation unit. This makes it possible to avoid a situation where the battery is fully charged when regenerative braking can be applied.
The contents of the patent documents, which are enumerated as the conventional technologies, may be introduced or incorporated by reference for the explanation of technical elements described in this specification.